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Surface Water and Well Survey <br /> - ort <br /> C A M B R I A and CPT O l SiInvestiitte No ion11p193 <br /> • Stockton, California <br /> December 16, 1999 <br /> INVESTIGATION RESULTS <br /> Site Hydrogeology The soils encountered beneath the site consisted of several feet of fill and up <br /> to 5 feet of clay which are underlain by silt and sand mixtures to the total depth explored of 30 feet <br /> bgs CPT electric logs were more detailed but generally consistent with adjacent boring logs based <br /> on soil samples collected at 5-foot intervals For example, the CPT electric logs indicate the <br /> presence of several clay or silt intervals that were not described in adjacent borings During <br /> sampling, groundwater was encountered at approximately 13-14 feet bgs <br /> Sod Analytical Results One or more soil samples were analyzed for GRO, BTEX, MTBE and <br /> TAME depending on field observations and sample recovery (see Table 2) No BTEX <br /> constituents were reported in the analyzed soil samples Except for 14 mg/kg in sample CB-1-13, <br /> 27 mg/kg in sample CB-3-13 5 and 0 74 mg/kg in sample CB-4-13 5, no GRO was reported in the <br /> analyzed soil samples MTBE was reported at concentrations of 0 010 to 28 mg/kg in analyzed <br /> samples from bonngs CB-1, CB-2, CB-3 and CB-4 No MTBE was reported in the analyzed <br /> samples from borings CB-5 and CB-6 Except for 0 058 mg/kg in sample CB-3-13 5, no TAME <br /> was reported in the analyzed soil samples <br /> Grab Groundwater Analytical Results Grab groundwater samples from depths of 16-17 feet bgs <br /> (shallow samples) and 29-30 or 34-35 feet bgs (deep samples) were analyzed for GRO, BTEX, <br /> MTBE and TAME (see Table 3) Shallow samples from borings CB-1, CB-3 and CB-4 reported <br /> more than 10,000 gg/1 of GRO and MTBE and more than 25 gg/l of benzene and TAME In <br /> addition, the shallow sample from boring C13-4 also reported 8 0 gg/l toluene, 160 ggfl of <br /> ethylbenzene and 110 ggll of xylenes Where reported in deep samples from borings CB-1, CB-3 <br /> and CB-4, GRO, MTBE and TAME concentrations were at least an order of magnitude lower than <br /> in the shallow samples No BTEX constituents were reported in the deep samples Shallow and <br /> deep samples from borings CB-2, CB-5 and CB-6 reported less than 150 gg/l of GRO and MTBE, <br /> and no BTEX, or TAME <br /> 8 <br />